Property owners in the Chicago area who have suffered through flooding in the past face the possibility for more of the same Thursday and Friday, as hard rains continue to pound saturated ground.

Additional rounds of heavy thunderstorms could dump another 1 to 2 inches by Thursday night, the National Weather Service said, on top of 1 to 2 inches that fell Wednesday, raising many area waterways above flood stage.

A flood watch remained in effect through Friday morning for northern Illinois and Indiana, including Cook, DuPage, Kane, Lake, McHenry and Will counties.

Emergency crews worked Wednesday to prepare for the worst along the Des Plaines and Fox rivers, filling sandbags and warning residents to move valuables out of basements.

Kurt Woolford, of the Lake County Stormwater Management Commission, said parts of Lake County could experience "moderate to major flooding" starting Thursday and heading into the weekend.

In Gurnee, the deluge could lead to a replay of floods that swamped roads and buildings in 2007.

Officials were preparing for the Des Plaines River to rise to 10.5 feet — 3 feet above flood stage — in the Gurnee area, according to U.S. Sen. Mark Kirk's office, putting roadways and structures at risk for flooding.

Gurnee resident Elmer Fallos stood in the bed of a pickup truck Wednesday, handing sandbags to his wife and daughter, who placed them in stacks of three along the outside their house.

"We're just protecting what we worked so hard for," said Fallos, who has lived in the area for 20 years.

Down the street, a group of about 80 volunteer seamen from Naval Station Great Lakes piled sandbags around storefronts and restaurants. Meanwhile, village workers delivered pallets of sandbags on forklifts to residents and business owners.

Resident Steve Wantoch huddled underneath an overhang at Gurnee Community Church as he waited for village maintenance workers to bring in 3-feet-tall concrete barriers and sandbags.

The Public Works Department in neighboring Libertyville also made sandbags available for residents Wednesday.

"We are hoping for the best, but we're planning for the worst," said Mike Brady, an assistant public works superintendent for Libertyville.

North and west of Chicago, along the Fox River and Chain O' Lakes, high waters and miserable weather prompted officials to close the entire waterway system to traffic.

Floating debris, submerged piers and swift currents led the Illinois Department of Natural Resources to ban boat traffic from the Wisconsin state line to the Montgomery dam south of Aurora. Officials said the ban will remain until they decide the waters are no longer dangerous.

McHenry County officials warned of flooding in 15 neighborhoods along the waterway that have a history of such problems, including parts of Spring Grove, Port Barrington and Algonquin, as well as some areas along the Kishwaukee River.

Stormwater flows into McHenry County from southwest Wisconsin and parts of Lake County, where watersheds were full, county spokesman Adam Lehmann said.

"If they get rain, it will flood," Lehmann said, "and it's raining already."

The water level at Chain O' Lakes reached 6 feet Wednesday — about a foot short of levels that caused flooding in the area in August 2007. It was expected to continue rising.

"It definitely could be very serious," Woolford said.

In far northwest suburban Johnsburg, officials issued a flood alert and put out a pile of sand and sandbags at Village Hall for people to fill their own.

Downstream in Kane County, flooding affected traffic Wednesday at Randall and Higgins roads and at Illinois Highway 47 and Plato Road, according to the Office of Emergency Management. Subdivisions along the Fox River near East Dundee and north of St. Charles were areas of concern, where flooding in 2007 and 2008 forced evacuations, in some cases by boat.